How to Switch Users in Ubuntu (Beginner-Friendly Step-by-Step Guide)

Switching between users is a very common task in Ubuntu, especially when you’re managing a VPS, maintaining a server for multiple developers, or simply testing permissions under different accounts.

Whether you’re using Ubuntu on a desktop or running it headless on a cloud server, there are several reliable ways to switch users safely. This guide walks you through all practical methods, explains when to use each one, and highlights common mistakes to avoid.

Why You Might Need to Switch Users in Ubuntu

Before diving into commands, it helps to understand why switching users matters:

• Running administrative tasks as root or another privileged user
• Testing file permissions or application behavior under a different account
• Managing multi-user servers (shared VPS, staging environments)
• Improving security by avoiding unnecessary root access

Ubuntu is designed around the idea of least privilege, so switching users correctly is an essential skill.

Method 1: Switch User Using su

The su command (short for substitute user) allows you to switch to another user account.

Basic Syntax

su username

Example:

su john

You’ll be prompted to enter john’s password, and once authenticated, your shell will switch to that user.

Switch to Root User

su -

or

su root

Note: On Ubuntu, the root account is disabled by default. If root login is not enabled, this command will fail.

Key Things to Know About su

• Requires the target user’s password

• Does not load the full login environment unless you use su -

• Less commonly used on Ubuntu compared to sudo

Method 2: Switch User with sudo su (Most Common on Ubuntu)

Ubuntu encourages the use of sudo instead of direct root access.

Switch to Root Using sudo

sudo su

or to load the full root environment:

sudo su -

This uses your own password, not root’s password.

Switch to Another User with sudo

sudo su - username

Example:

sudo su - deploy

This is extremely useful on VPS servers where you don’t know (or don’t want to use) other users’ passwords.

Method 3: Use sudo -i (Recommended for Root Access)

If your goal is to become root, this is the cleanest and safest method:

sudo -i

This command:

• Switches to root

• Loads root’s environment

• Preserves Ubuntu’s security model

For most administrators, sudo -i is preferred over su.

Method 4: Switch User Temporarily for a Single Command

If you don’t need a full shell, you can run a command as another user.

Run Command as Another User

sudo -u username command

Example:

sudo -u www-data ls /var/www

This is ideal for:

• Testing permissions

• Running scripts as service users

• Avoiding unnecessary shell switching

Method 5: Switch Users in Ubuntu Desktop (GUI)

If you’re using Ubuntu with a graphical interface:

1. Click the system menu (top-right corner)

2. Select Log Out

3. Choose another user from the login screen

Some desktop environments also support Fast User Switching, allowing multiple users to stay logged in simultaneously.

Common Mistakes to Avoid

• Using su without -, which may cause missing environment variables

• Running daily tasks as root, increasing security risk

• Forgetting to exit root, especially on production servers

• Changing file ownership unintentionally while logged in as root

Always double-check which user you’re currently using:

whoami

FAQ:

1. What’s the difference between su and sudo su?

su requires the target user’s password, while sudo su uses your password and respects Ubuntu’s permission system. On Ubuntu servers, sudo su is far more common.

2. Why does su root not work on Ubuntu?

Ubuntu disables direct root login by default for security reasons. You should use sudo su or sudo -i instead.

3. Which is better: sudo su or sudo -i?

For root access, sudo -i is generally recommended because it cleanly loads root’s environment and follows Ubuntu best practices.

4. How do I know which user I’m currently logged in as?

Run:

whoami

or

id

5. Can I switch users without a password?

Only if your account has sudo privileges. Otherwise, switching users always requires authentication.